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Oak Gall

Bug eggs on Oak leaves
Location:  Southeastern Iowa
August 16, 2010 2:35 pm
The attached photos show a multitude of bug eggs on the leaves of the oak tree in my backyard.
I cannot identify what bug these eggs are associated with. I would like to know if there is any danger to the tree’s health or to my home from these bugs.
Jay D

oak gall jay 300x206 Oak Gall

Oak Gall

Hi Jay D,
This is not an egg.  It is a Gall.  A Gall is a growth on a plant caused by an wasp, midge, mite, or occasionally another type of insect.  According to BugGuide: “There are more than 2,000 gall-producing insects in the United States; 1,500 are either gall gnats or gall wasps.“  The insect produces an enzyme that causes the plant tissue to grow in a deformed manner, and this growth serves as food for the developing gall larvae.  It is generally believed that the Gall does not harm the plant.  We believe your Gall is a Gall Wasp in the family Cynipidae, but we could not find a conclusive match on BugGuide.  There is one image of an unidentified Gall Wasp Gall on BugGuide that looks similar to your Gall.   BugGuide gives this advice for Gall identification:  “Gall insects (and mites) are usually highly specific about what kind of plants they use, and even what part of the plant. To maximize your chances of getting a gall identified, record the plant species (include photos of the leaves, flowers, fruits, etc. if you’re not sure), and if it’s a leaf gall, note the position on the leaf (if it’s not obvious from the photo): upper side or underside; midrib, side vein, or somewhere else. Also note whether or not the gall is detachable, the size of the gall, and anything else distinctive about it that may not be clear in the photo. With oaks in particular, which are hosts for hundreds of kinds of galls, every little detail can help to narrow down the options.“  An interesting side note is that Alfred Kinsey who shot to notoriety in the mid twentieth century with his ground breaking studies on human sexuality began his professional career as an entomologist who specialized in the study of Gall Wasps.  He approached his studies on human sexuality with the same rigor that he used in collection over 1 million specimens of Gall Wasps.

oak galls jay 300x206 Oak Gall

Oak Galls

Posted 16 August 2010 § Gall Wasps ‡ Comments (0) °
What's That Bug? does not endorse extermination

Unknown Galls

bug larvae on Spanish Stopper
Location:  Florida Keys
August 11, 2010 11:30 pm
Hi!
I’m just curious as to what these things are on the underside of Eugenia foetida.
Susan

unknown galls eugenia foetida susan 300x235 Unknown Galls

Unknown Galls

Hi Susan,
These appear to be Galls.  Galls are growths that appear on plants and they are often caused by insects, but not always.  We have not had any success determining what has caused these Galls.  When they are caused by insects, they are usually very plant specific.  Perhaps one of our readers will be able to assist with the proper identification of your galls.

Thanks Daniel!
Everyone from the park (volunteer for Dagny Johnson Bot. SP) tells me they are galls but that seems to be enough of an answer. I would like to know more. I would guess that they are caused by insects as they are on so many Spanish Stopper especially this year.
Susan

Posted 12 August 2010 § ‡ Comments (0) ° Tagged:

Grape Tube Gallmakers from Italy

What is This?
July 8, 2010
Dear Bugman,
Recently, I went hiking to an old monastery in Turin, Italy. The trail was punctuated by large cement crosses that had something to do with the myth of the Stations of the Cross. Worried about having a Jesus overdose, we sought an alternate route. Along the way, we came across this deformed tree. Thinking it was perhaps the work of Satan, we went back to the JC trail.
I am not convinced that these odd thorny growths are from the devil’s hand. Seems he could do a lot better than this. I suspect it’s a bug!
Any ideas?
Regards,
Godless Hiker
Turin Italy

grape tube galls lisa italy 300x206 Grape Tube Gallmakers from Italy

Grape Tube Gallmakers

Dear Godless Hiker,
These odd thorny growths appear have been produced by the Grape Tube Gallmaker, Cecidomyia viticola, a species of Midge.  The plant appears to be a wild grape which would support our identification.  We ran a similar photo from Alabama in 2008.  Galls are generally considered to be growths on plants that may be caused by insects including wasps and flies, or by mites or other arthropods.  BugGuide indicates: “Gall insects (and mites) are usually highly specific about what kind of plants they use, and even what part of the plant. To maximize your chances of getting a gall identified, record the plant species (include photos of the leaves, flowers, fruits, etc. if you’re not sure), and if it’s a leaf gall, note the position on the leaf (if it’s not obvious from the photo): upper side or underside; midrib, side vein, or somewhere else. Also note whether or not the gall is detachable, the size of the gall, and anything else distinctive about it that may not be clear in the photo. With oaks in particular, which are hosts for hundreds of kinds of galls, every little detail can help to narrow down the options.”

grape tube galls italy lisa 300x207 Grape Tube Gallmakers from Italy

Grape Tube Gallmakers

Posted 09 July 2010 § Midges ‡ Comments (0) °
What's That Bug? does not endorse extermination

Gall on Artemesia

Galls on Artemesia tridentata
March 13, 2010
Here is a photo of some different galls then I sent before. These are more common and are less rounded and in multiples joined together. I’m not sure if its a fly, beetle or mite. One guy said those other galls might be cecidomyiid fly. Both are on Artemesia tridentata.
Ernie
Okanogan, Wash.

gall sage ernie 300x257 Gall on Artemesia

Galls on Artemesia

Hi again Ernie,
Thanks for sending in more photos of Galls.  Perhaps an expert in Galls will be able to do a conclusive identification.

gall sage ernie cu 300x202 Gall on Artemesia

Galls on Artemesia

Posted 13 March 2010 § ‡ Comments (1) °

Unknown Galls on Sagebrush

SAGEBRUSH GALL
March 9, 2010
FOUND THIS INTERESTING GALL ON SAGEBRUSH (ARTEMESIA TRIDENTATA) IS THIS THE WOOL SOWER CALLIRHYTIS SEMINATOR OR RHOPALOMYIA?
ERNIE
OKANOGAN, WASH.

galls sage ernie 300x204 Unknown Galls on Sagebrush

Unknown Gall on Sage

Hi Ernie,
Galls, unusual growths on plants, are often caused by insects, but there might be other reasons that the plant tissue becomes distorted and produces the odd growths.  There is a nice online piece on Gall Making Insects by John A. Byers that has good information.  This is neither a Wool Sower Gall and we are not certain if this growth on sage is caused by a Midge in the genus Rhopalomyia without doing additional research.  We did find a paper online that was published by the Journal of the Kansas Entomological Society that mentions, but doesn’t picture, a Fruit Fly, Eutreta diana, that is called a Sage Stem Galling Fly.  We found the fly pictured on the Diptera Site, but again, a photo of the actual Gall produced by the fly has eluded us.

Posted 09 March 2010 § ‡ Comments (2) ° Tagged:
What's That Bug? does not endorse extermination

Creosote Gall

Gall or nest?
August 3, 2009
Hi guys!
I absolutely love your site, and tell all my friends about it! I found a very alien object clinging to a creosote bush behind my house, in Tucson AZ. It is a leafy sphere, about the size of a quarter. The leaves (which don’t look anything like those the creosote leaves) are arranged in whirls, like a grassy daisy, and there is a tiny hole in the center of each. Coming out of each hole are discarded exoskeletons, like those of the grain moth larvae you find in boxes of rice and pancake mix. They are probably only 4 or 5mm long. There is also a bit of silk strewn around the whole thing, which gives it a dewy, sticky look, but I haven’t touched it because I don’t want to be impregnated by some alien insectoid race. What kind of bug could construct such a crazy looking (and beautiful) nest? Or is it a gall of some sort? I am so very curious…
Thanks for your help!
Emily Rush
Tucson, Arizona, USA

Creosote Gall

Creosote Gall

Creosote gall
August 3, 2009
Hi!
Me again. After writing to you, I decided to google “creosote gall”. Don’t know why I didn’t do that first, I guess I was just excited to send you a pic of something you might not have seen before. Apparently my mystery alien sphere IS a gall, caused by, wonder of wonders, a creosote gall midge! I couldn’t find a picture of one though. Any help in this area?
Thanks again!
Emily Rush
Tucson, Arizona, USA

Hi Emily,
Thanks for sending us your photo of a Creosote Gall and doing the subsequent research.  BugGuide has images of the Creosote Gall filed under the species Asphondylia auripila with the information:  “Larvae form galls in creosote bush (Larrea tridentata),” but if you go to the genus Asphondylia and browse, you will see some images of related Midges that probably look very similar to the Creosote Gall Midge. The only species on BugGuide with images of adults is Asphondylia solidanginis. Species in the same genus often have visual similarities and an expert is required to differentiate one from another.  Unlike the Oak Gall we just posted which was formed by a small wasp, the Creosote Gall is formed by a Midge that is in the order Diptera and is classified with the flies.  The Creosote Gall is a deformation of the plant with the leaves and stems stunted to form the Gall.  If you follow the taxonomy on BugGuide back to the Family Cecidomyiidae, you start to get a bit more information, including:  “Minute, delicate flies with long legs and usually relatively long antennae, and with reduced wing venation” and “more than 1,200 species in 170 genera in North America.” There are images of many different species on the Cicidomyiidae page of the Forestry Images website.  Some of the members of the family include the Skeletonweed Gall Midge and the St. John’s Wart Midge.  Those should give you some idea of what the Creosote Gall Midge looks like.  Again, thanks for sending us your photo.

Thanks Daniel!
I hope I can catch a midge in action. By the way, the root borer you posted is a Palo Verde beetle (Derobrachus geminatus). We have lot’s of them in Tucson- they’re HUGE, and they’re really active right now, during the monsoon. I like their fancy spiked collars! Here’s another!
Emily

Posted 03 August 2009 § Midges ‡ Comments (2) °

Oak Apple or Oak Gall

Insect egg ball
July 31, 2009
Hi,
I keep finding these egg balls under an oak tree in my yard. Can you tell me what comes out of these? (The second picture shows their exits.) The wall material is paper thin and very brittle. They are about the size of a golf ball, beige, and bumpy.
Thank you.
Todd Shinn
Salisbury, NC

Oak Gall

Oak Gall

Hi Todd,
This is the Gall or Oak Apple formed by some species of Gall Wasp, a tiny wasp in the family Cynipidae.  The larval Gall Wasp creates the Gall as part of its growth process and the Galls do not harm the trees. There are numerous species and according to BugGuide: “Many different cynipid wasps form large, spherical galls on oak leaves, some of which are called “oak apples.” As with most galls, ID requires knowing the species of oak. It is also critical to look at the internal structure:  Even then, there are some very similar ones, and it may be necessary to examine the adult wasp that emerges.“  A British Website has a photo that matches your Gall, and it is identified as Biorhiza pallida, but we believe your new world species is not the same. According to BugGuide there are  “Over 750 species in North America in 49 genera” and “Small to minute, usually black, with characteristic shape: the abdomen is oval and somewhat compressed and shiny, the second tergum covers a good part of the abdomen. Each species makes a characteristic gall on a specific part of the plant. Many make galls on oaks. Most have a complex life cycle with a parthenogenetic generation and a sexual one. Each generation makes galls of a different appearance and on different parts of the plant.“ The recognized expert in this family is Charles Kinsey who died about 50 years ago after achieving worldwide fame for his studies of male and female sexuality.

Posted 02 August 2009 § ‡ Comments (0) °

Oak Galls

I found cocoon-like brown hard masses on the front side of a leaf.What are they???
Wed, Oct 8, 2008 at 6:13 PM
I was sweeping off the porch at the campground that I stayed at during the summer/fall.We had a big wind storm come thru and there were a bunch of leaves on the porch.On a lot of the leaves,I noticed these little hard brown cocoon-like circles on the front side of a leaf.I was thinking that cocoons were laid on the under part of the leaf,and that they were soft to touch,but these are hard and round.So I decided to cut one open and inside are these tiny red-orange color worm-like things inside.They moved a little bit,so I just thought that they were a worm of some kind.I’ve looked all over the internet and came up with nothing.Finally I posted my question and someone told me to contact you.I have pictures of the “cocoons” and the “worms” inside.The worms are very small and hard to see on the picture.Please help me identify w hat I’ve found!
Curious Nature Lover
Shreve,Ohio

Oak Leaf Galls

Oak Leaf Galls

Dear Curious,
Galls are growths on plants that may be caused by insects, mites, bacteria or fungus.  The Galls may occur on the leaves, stems, roots or flowers of the plants.  Most often, the Galls are plant specific.  We located a drawing in a very old copy of a text by Frank E. Lutz that we own.  The drawing is of a Oak Leaf Gall known as Dryophanta polita.  Since the text is a field guide, there was no additional information beyond the identification.  When we tried a web search of that name, be were led to several online texts that we could not access entirely.  One such text is Insects Affecting Park and Woodland Trees and the google teaser is “Oak leaf bullet gall Dryophanta polita Bass. A small, globular gall occurs in
numbers in August … “  Another reference led to the common name Polished Oak Gall.  At this point, we can only speculate that Dryophanta polita is a Gall Wasp in the family Cynipidae, but curiously, it is not listed in BugGuide’s taxonomy for the family.  Another interesting side note is that Alfred Kinsey, most widely known for his studies of human sexuality and his best selling books in the 1950s, was first and foremost an entomologist who specialized in Gall Wasps.

Dissected Oak Leaf Galls

Dissected Oak Leaf Galls

Posted 09 October 2008 § ‡ Comments (0) °

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